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Clarifying Misconceptions About Allergen Immunotherapy

I was recently embroiled in an online discussion with several pulmonary and primary care colleagues regarding the efficacy of Allergen Immunotherapy in the treatment of asthma and the future of sublingual immunotherapy, which I think is worth sharing. Let’s start off with some Frequently Asked Questions:Whare are “Allergy Shots”?
Allergen immunotherapy or “allergy shots” is a form of treatment aimed at decreasing sensitivity to substances called allergens which were identified by allergy testing. Allergen immunotherapy involves injecting increasing amounts of these allergens to a patient over a period of time to decrease the patient’s sensitivity to the allergens, prevent development of new allergies, and in children, prevent progression from allergic rhinitis to asthma. Allergen immunotherapy can lead to long-lasting relief of allergy symptoms after treatment is discontinued.

How does Allergen Immunotherapy work?
Allergen immunotherapy works like a vaccine. Your body responds to injected amounts of a specific allergen by developing immunity or tolerance. There are two phases to immunotherapy: a build-up phase and a maintenance phase.

When will the allergy shots start working and when can I stop my meds?
The benefits of allergen immunotherapy, in terms of reduced allergy symptoms, can begin during the build-up phase but may take as long as 12 months on the maintenance doses. It is important to continue taking allergy medications as prescribed together with the allergy shots during the build-up phase. Later, when your symptoms improve, you may discuss with your doctor whether you can discontinue some of your allergy medications.If you do not get your allergy shots on schedule, it will take longer to reach the maintenance dose and longer for the allergy shots to work effectively.

How long do I have to take the Allergy shots?
With currently available allergen extracts, maintenance treatment is generally continued for 3 to 5 years after the build-up phase, which can take up to 6 to 9 months. The majority of inidividuals experience lasting remission but a minority may relapse after discontinuing immunotherapy, therefore the decision to stop must be individualized.

How effective is allergen immunotherapy?
Immunotherapy is successful in up to 90-95% of patients with seasonal allergies and up to 85% of patients with year-round allergies.

Asthma is a multifactorial disease. Allergic rhinitis/ sinusitis has definitively been shown to contribute to the severity of asthma in patients. One of the modalities used to treat allergic rhinitis/ sinusitis and asthma is allergen immunotherapy (IT). By no means is anyone suggesting that allergen immunotherapy be used INSTEAD OF inhaled steroids, however allergen IT does have solid data to show its efficacy when used in conjunction with other modalities.

This is topic has been addressed by the American College of Allergy, Asthma, and Immunology in its position paper on the Cost Effectiveness of Immunotherapy for Asthma.

Regarding sublingual immunotherapy, there is considerable evidence that sublingual immunotherapy for allergic rhino-conjunctivitis has been effective using high doses of grass extract. This is commercially available and used in Europe, but has yet to have FDA approval in the USA. Some studies showing efficacy are cited below:
1. Calderon M, Essendrop M. Specific immunotherapy with high dose SO standardized grass allergen tablets was safe and well tolerated. J Investig Allergol Clin Immunol. 2006;16(6):338-44. 2. Nelson HS. Advances in upper airway diseases and allergen immunotherapy. J Allergy Clin Immunol. 2007 Feb 8; [Epub ahead of print]
That being said, appropriate dosing and efficacy with multiple SL allergen combinations are still an issue.

The “sublingual immunotherapy” that is pure quackery has been used to treat “idiopathic environmental intolerance” (IEI) by means of “neutralizing” extracts administered as sublingual drops usually at such a miniscule dose that it is really only placebo. See the AAAAI position statement on this.

For a tragic example of the use of these “neutralizing sublingual drops” for treatment of IEI or “multiple chemical sensitivity syndrome” see the “Tragic Example” post on this blog.

Thanks Dr. de Asis. Are there particular patient groups for whom you would recommend AIT and, equally, patients who should avoid it? It is a treatment that is very difficult to access in the UK, so most of us don’t know who should or shouldn’t be considering it.

Thanks for the comment Shinga and HCW. The clinical indications for allergen immunotherapy are listed in this table from the AAAAI Practice parameters (http://www.jcaai.org/PP/images/1TT5.gif) and as summarized below:
“Aeroallergen immunotherapy should be considered for patients who have symptoms of allergic rhinitis or asthma after natural exposure to allergens and who demonstrate specific IgE antibodies to relevant allergens. Evaluation of the patient should include a medical history and an appropriate physical examination. The severity and duration of symptoms also should be considered in evaluating the need for specific allergen immunotherapy. Symptom severity can be defined by subjective as well as objective means. In addition, specific allergen immunotherapy should be considered if the patient wishes to avoid long-term pharmacotherapy. Time lost from work, visits to the emergency department or physician’s office, and response to conventional medications are also important objective indicators of disease severity.

Patients with allergic rhinitis who can not sleep because of symptoms or whose daytime symptoms interfere with their work or school performance should be considered strong candidates for specific allergen immunotherapy. The effect of the patient’s symptoms on quality of life and the patient’s responsiveness to other forms of therapy, such as allergen avoidance or medication, should also be considered. Adverse effects of medication also should favor a decision to initiate allergen immunotherapy. Immunotherapy is usually not more costly than pharmacotherapy over the projected course of treatment.

Allergen immunotherapy for allergic rhinitis may have benefits that continue after immunotherapy is stopped. Preliminary results suggest that it may reduce the risk for the development of asthma in children.123,124,125,126 These benefits of immunotherapy should be discussed with patients and may provide a clinical indication for initiating immunotherapy in selected patients with allergic rhinitis.

Coexisting medical conditions should also be considered in selecting patients who may benefit from allergen immunotherapy. Patients with moderate or severe allergic asthma and allergic rhinitis should be managed aggressively with a combined regimen of allergen avoidance and pharmacotherapy; these patients may also benefit from allergen immunotherapy.6,7 Patients with severe or uncontrolled asthma may be at increased risk for systemic reactions to immunotherapy injections.150

Special Precautions in Patients With Asthma
Summary Statement 18. Patients with severe, poorly controlled asthma are at higher risk for systemic reactions to immunotherapy injections. (C)

Patients with severe, poorly controlled asthma are at higher risk for systemic reactions to immunotherapy injections than patients with stable, well controlled asthma.132,150 One survey found that deaths from immunotherapy were more common in symptomatic (as compared with asymptomatic) patients with asthma.136”

Patients who are mentally or physically unable to communicate clearly and patients who have a history of noncompliance may be poor candidates for immunotherapy. If a patient can not communicate clearly with the physician, it will be difficult for the patient to report signs and symptoms, especially early symptoms, suggestive of a systemic reaction.

Pstients with poorly controlled asthma or have lung capacity less than 1.5 L are generally not considered for AIT except under extreme circumstances. Patients who cannot comply with the AIT schedule should also not be considered since adherence to the schedule is necessary for therapeutic success.
I hope this was helpful, if you need more info, please let me know.

Great post – one nitpick – “whare”? Should be “what” I think. Not saying my typing is perfect or anything!

Who on earth was arguing with you, an allergist, about immunotherapy? Do they not understand that it is a well-established and effective therapy for the majority of patients? Not me, but I’m odd. Allergist and I agreed to quit immunotherapy when I went into systemic reactions several times during treatment.

Thanks for the tip HCW! Yes, unfortunately I think it’s the same practitioner.I’ve linked the “Tragic Misinformation” post to Orac’s post so readers of that post can see what big business “neutralizing extracts” and “chelation therapy” can be.